Where is the best place to begin here? I've looked at the challenges in the past and have felt a bit intimidated.
I use codechef and hackerrank regularly and am currently working though advent of code, but am willing to take a look here once advent of code ends!
The best way to explore Topcoder platform is via the member dashboard: https://www.topcoder.com/home, you can find the latest information about recent updates from our challenges, learning materials, gigs, news feed, members benefit, main navigations, etc there.
Also, what is your interest in our platform? is it to get a job/getting a cash money, learning about coding (development or competitive programming?) and discuss some topics related to specific technology,or just having fun with people that have same interest with you?